The Nettlebridge valley

The Somerset
Coalfield stretches from the Mendips north to Pensford and Timsbury,
and is centered around the town of Radstock. It was in this coalfield
that William 'Strata' Smith, the so-called 'father of English geology',
first put together his ideas on stratigraphy. The southernmost
part of the coalfield extends south to the Mendip Hills. Here the
Mells River has incised the Nettlebridge
valley, cutting through a cap of Dolomitic Conglomerate to
expose the Upper Carboniferous Coal Measures beneath. The area
contains a wealth of interesting geology, industrial archaeology
and wildlife, as well as several nature reserves.

Coal mining

Coal was probably worked in Roman times but mining began in earnest
in the 1600s. The early pits exploited surface outcrops, but by the
1790s, shafts up to 150 m deep were being sunk. However, the rocks
are highly contorted and are often vertical or even overturned, which
has made coal mining in the area very difficult. Because of the thin
near-vertical seams, the miners employed techniques more akin to
Cornish tin mines than traditional methods used elsewhere. However,
the narrow contorted seams made production expensive and competition
from more economical coalfields led to the closure of the last remaining
pit in 1973.

The
remains of several pits can be seen in the valley including
Moorewood Colliery near Upper Benter, Strap Pit (renamed Mendip
Colliery in 1953 by National Coal Board) and New Rock Colliery.
Abundant evidence of pre-18th century mining can be seen in Harridge
Wood, Edford Wood and around Benter. In these areas the coal
seams outcrop at the surface and the remains of old bell pits,
spoil heaps, adits and shafts create a very hummocky topography.

There were plans to connect
the mines in this area to a proposed Bristol–Poole canal. In the
end, only about 13 km of canal was cut, the remains of which can
be seen around Edford and Coleford where the canal crossed a valley
by a two-arched viaduct known locally as the Hucky Duck. A footpath
now runs along its course.

More information about coal mining in Somerset is available from
Radstock Museum.

Map of the old coal mines. (Click to enlarge).

The pit head at the Mendip colliery, 22 August 1962. (Click
to enlarge).

Flora and fauna

The Nettlebridge contains several nature reserves including Harridge
Wood and Edford
Wood. Both are thought to be very old, but have been locally
coppiced or felled and replanted with conifers. Where the woods
retain their semi-natural character, there is a very rich woodland
flora. The distribution of species closely reflects underlying
variation in geology, soil wetness and pH. The area is particularly
good for bats, including
rare greater and lesser horseshoe bats, which roost in caves
and buildings nearby. Daubenton's bats forage along rivers and
streams, particularly in the western arm of Edford Wood.